Does anyone publish a horsepower number for F-150 headers?
Some do. Of 13 F-150 headers in our catalog, 3 publish a horsepower figure and 10 do not. Every figure below is labeled with where it came from: an independent test, the manufacturer's own claim, or an estimate from comparable hardware.
the ones that do
why the rest don't
https://www.enginelabs.com/engine-tech/exhaust/determining-header-design-affects-output-coyote-5-0/ - checked 2026-07-12.
NONE PUBLISHED - checked Stainless Works' own product page (stainlessworks.net/2015-20-f-150-5-0l-long-tube-header-kit-factory-connect) on 2026-07-26: NO numeric hp or torque figure. Page carries a "Dyno-Proven Power" banner and the phrase "maximum power" but publishes no measured result. Dyno wording without a number must not be read as a tested figure. Kit is described as including "EPA compliant" high-flow catalytic converters; no CARB EO number is published, so no California street-legal claim is made here.
NONE PUBLISHED - verified 2026-07-26: product page states no horsepower or torque figure. Source checked: https://stainlessworks.net/2021-2025-f-150-5-0l-long-tube-header-kit-factory-connect/.
NONE PUBLISHED - checked Kooks' own product page (kooksheaders.com/products/1371h230) on 2026-07-26: no hp, torque, dyno or rwhp gain figure stated. The page does carry a CARB notice, quoted verbatim: "California laws prohibit the use of any aftermarket exhaust part or system that modifies, removes or replaces original equipment catalysts unless the California Air Resources Board has issued an Executive Order regarding such part or system or unless the part or system is exempted by being used only on racing vehicles on closed courses." No CARB EO number is published for this kit, so no street-legal claim is made here. Prop 65 warning also present (chromium, nickel).
related questions
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Every figure on this page is read from our catalog when the page loads, and every gain carries the label of where it came from. Gains do not simply stack. Prices are list prices at named retailers and can lag; confirm at checkout.